Fluid compass



Nam 5, EQB H. R EKEBRG FLUID COMPASS 'Filed March 29, 1957 Patented Nov. 15, 1938 y Henning Rudolf Ekeherg,

Stockholm, Sweden, as-

signor to Aktiebolaget Svenska Elektro-Inldustri Companiet,

Stockholm, Sweden, a

limited company of Sweden Application March 29, 1937, Serial No. 133,667

In Sweden April 8, 1936 the upper side of the casing remains substantially l constant. y A

According to the invention, the rst-mentioned object is realized by the liquid beingenclosed within a chamber formed of a cover portion of transparent material and -a. thin resilient bottom portion secured thereto, this bottom portion being adapted to adjust itself to the changes of volume of the enclosed liquid caused by variations in temperature.

The latter object is fullled, according to `the invention, by the compass needle being arranged on a pin Whichis carried by an intermediate partition or bridge, a frame or the like arranged between the transparent cover and the resilient bottom, the said partition or the like being provided with openings and being so arranged that the distance of the needle from -.the cover remains substantially consta-nt in spite of the move-v ments on the resilient bottom.

Qther features characteristic of the invention will be explained more fully in the following with reference tothe f orms of embodiment illustrated in the accompanying drawing.

Fig. 1 shows an embodiment in longitudinal vertical section. Fig. 2 is a plan view of Fig. 1. Figs. 3 and 4 represent details.

In Fig. 1, I designates the cover portionv formed of cellon, Celluloid, glass or other suitable transparent material, said cover being provided with av downwardly directed annular flange 2. Pasted to the inside of the flange 2 is the upwardly dlrected annular flange I2 of aresilient bottom 9 of thin cellon or sheet metal, such as aluminiumplate or the like. The ilange I2 tightly surrounds the upwardly directed annularviiange II oi an intermediate partition 3 of comparatively thick sheet-metal, such as aluminium-plate, which is bulged upwardly. The intermediate. partition 3 ldivides the space between the cover I and the bottom 9 into two chambers IU and I4. Secured to the centre of the partition 3 is the pin 4 carrying the holder 6 of the compass needle 5, said holder forming a tting for the jewel I, for lnstance agate, which rests on the point of the pin 4. The holder 6 is provided with a disk-like an arrangement for v projection 8 adapted'to limit the movements of the compass needle by abutting against the cover I, so that the. compass needle cannot fall oir the. pin 4. y l.

The liquid, such as'petroleum, which serves to 5 damp the swinging movements of the compass needle is lled in through a little aperture l5 in the cover portion I5. To 'facilitate the lling, and in order with certainty to remove all air out of the casing 'as well as from the damping liquid, 10' the filling is preferably effected under vacuum. Secured to the outside of the annular flange 2 of the cover portion is a ring I 6, for instance of aluminium, rhodoid, cellon or the like, said ring serving as a fitting or attachment for the 15.

compass casing.

The annularlanges II and- I2 of the partition 3 and the bottom 9 respectively pass over into the partition 'and the .bottom respectively through correspondingly curved portions, so that the 2g ilange I2 will enclose the outside of the flange II as tightly as possible. The ange I2 may be` curved inwardly and downwardly at the top, as shown in the drawing, so as to grasp about the upper edge of the flange Il. 25

Provided in the intermediate partition 3 are two openings I3 adapted to connect the space I0 with the space I4. In the embodiment shown, the .openings are radially arranged and extend4 outwardly so far as to pass into the curved portion connecting the partition 3 proper with its ilange I I. Any air bubbles occurring 'in the space Ill may thus be caused readily to escape through the openings I 3 byvtilting the compass casing.

After the lling of the casing has been completed, 35

the' aperture I5 is closed.

If desired, a ring IB, for instance of aluminium, rhodoid, cellon or the like, may be secured on the outside o1' the annular flange 2 of the cover, said ring I6 serving as' a iitting or attachment for the compass casing. To this end, it may be .provided 'with an annular plane flange II intended t'serve as being made from sheet-metal, such as aluw minium-plate. This, however, does not form any particularly characteristic feature of the invention, since the said bottom may be advantageously made from celluloid, cellon orother transparent material, for example. If the intermediate partition is made from opaque material, while the bottom portion 9 is made from some transparent material, it may be preferable to make thel intermediate partition `3 in the form of a vnarrow bridge with parallel edge portions I9, so that large openings are formed, through which the bottom portion 9 and any chart or map or the' like placed therebeneath. will beA easily visible. Such an alternative :construction is shown in Fig. 2 with chain dotted lines, the openings in thefintermediate;` partition being denoted by I8 therein.` y

If the bottoni portion 9 consists of transparent material, and if the j vintermediate-partition 3, should Isuch partition be brought into use, is transparent or provided`-withlargeopenings, it may be of advantage-'to provide the iirst-mentioned bottom'portionj with parallel lines for the purpose of orientation of the compass on a map.

If desired, the' intermediate partition may be provided with su'ch lines.

Obviously, the shape of the cover portion l may be varied within `widelimits.v For example, it may be bulgedln an accentuated,manner so as to form a portion of a spherical surface, which under-certain circumstances may beof advantage to facilitate reading of the compass.

, Furthermore, it is not necessary that the flange` l 2 surround the flange I2 of the resilientbottom ,iportion 9, the flange 2 being instead formed in a manner such as to be surrounded by the flange Il of the intermediatepartition 3.

Having now particularly described the nature of my invention andthe manner of its operation what I claim isz- Fluid compass comprising a cover of transparent material, a resilient bottom secured to said cover, a closed chamber between said cover and said bottom, said chamber being wholly illled with a damping fluid, an intermediate partition secured between the bottom and the cover anddividing theA chamber into an upper and a lower space, means of communication' between said spaces provided'in said partition, a compass needle in said. upper space, means secured to said partition for journalling the compass needle, an upwardly directed annular flange provided on said partition, an/,upwardly directed annular ilange provided on said resilient bottom, the last named flange being concentric with andtightly ysurrounding the first named flange, the upper edge of said flange of the resilient bottom being curved inwardly and then downwardly about the upper edge of Vsaid flange of the intermediate partition, a downwardlydirected annular flange provided on said transparent cover and concentric with and tightly surrounding said flange of said resilient'bottom, and pasting means between `said nanges of the bottom and the cover.

" HENNTNG RUDOLEEKEBERG. 

